Abstract: The present invention is moisture resistant chalk line composition comprising an effective amount of calcium carbonate, an effective amount of one or more dyes, and an effective amount of one or more hydrophobes, said effective amount of calcium carbonate comprises at least about 50% by weight of the composition, said effective amount of one or more dyes is selected from a range of about 0% to about 49% by weight of the composition, and said effective amount of one or more hydrophobes does not exceed about 30% by weight of the composition. The chalk line composition is useful for repeatedly marking guide lines with the same chalk line device on wet surfaces or moist environments. Also claimed is a method for repeatedly forming guide lines on surfaces utilizing a moisture resistant chalk line composition with a snap line from a chalk line device.